This invention relates generally, as indicated, to a helical splined rotary actuator, especially intended for use in controlling the movements of aircraft flight control surfaces and the like.
The actuator of the present invention is of a substantially balanced design including a dobule acting piston arrangement which operates in line to create substantially equal and opposite axial forces. Also, the actuator is desirably center mounted and has a center drive output to minimize distortion of the respective structures to which the center mount and center drive output are respectively connected resulting from the reaction torques produced in the actuator itself and to minimize the effect of large deflections of the structures on the actuator.
In such an actuator desing, it would be desirable to maximize the output torque for a given actuator envelope. Also, it would be desirable to make such an actuator lighter without sacrificing strength. Furthermore, it would be desirable to prolong the life of the actuator piston seals and reduce the chances of seal leakage.